> Hello Eric,>> I've recently tried to boot 2.6.35 (and -git) on one of my machines, and it> fails to boot. No messages are printed to the serial console. I have run git> bisect, and found that your commit cf7500c0ea133d is the cause.

This problem took a while to track down, but it should be fixed in thecommit below. Which linus merged today from the x86-urgent branch.

Thank you for the excellent bug report, and my apologies for missingthis the first time around.

This fixes a regression in 2.6.35 from 2.6.34, that is present for select models of Intel cpus when people are using an MP table.

The commit cf7500c0ea133d66f8449d86392d83f840102632 "x86, ioapic: In mpparse use mp_register_ioapic" started calling mp_register_ioapic from MP_ioapic_info. An extremely simple change that was obviously correct. Unfortunately mp_register_ioapic did just a little more than the previous hand crafted code and so we gained this call path.

Which turned out to be a problem because the local apic was not mapped, at that point, unlike the similar point in the ACPI parsing code.

This problem is fixed by mapping the local apic when parsing the mptable as soon as we reasonably can.

Looking at the number of places we setup the fixmap for the local apic, I see some serious simplification opportunities. For the moment except for not duplicating the setting up of the fixmap in init_apic_mappings, I have not acted on them.